See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/313833896 Mobile phone use and risk of brain tumours: a systematic review of association between study quality, source of funding... Article in Neurological Sciences · February 2017 DOI: 10.1007/s10072-017-2850-8 CITATIONS 0 READS 55 5 authors, including: Some of the authors of this publication are also working on these related projects: Biomarkers to enhance the accuracy and precision of prediction of short-term and long-term outcome after spontaneous intracerebral haemorrhage: a prospective cohort study View project Genetic Basis of stroke in India View project Pallavi Nair All India Institute of Medical Sciences 7 PUBLICATIONS 7 CITATIONS SEE PROFILE Amit Kumar All India Institute of Medical Sciences 80 PUBLICATIONS 227 CITATIONS SEE PROFILE Kameshwar Prasad All India Institute of Medical Sciences 290 PUBLICATIONS 3,936 CITATIONS SEE PROFILE All content following this page was uploaded by Pallavi Nair on 21 February 2017. The user has requested enhancement of the downloaded file.
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Mobile phone use and risk of brain tumours: a systematic ... · Amit Kumar [email protected] Kameshwar Prasad [email protected] 1 Department of Community Medicine, Postgraduate
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Mobile phones are now an integral part of modern telecom-
munication. The use of mobile phones is globally widespread
with high prevalence among almost all age groups in the
population, posing a potential public health concern. The use
of mobile phones has increased rapidly in recent years.
At the end of 2015, there were 4.7 billion unique mobile
subscribers globally, equivalent to 63% of the world’s
population. By 2020, almost three-quarters of the global
population will have a mobile subscription, with around 1
billion new subscribers added over the period [1].
Mobile phones emit electromagnetic energy waves,
which are classified as possibly carcinogenic to humans by
the International Agency for Research on Cancer [2]. This
has raised concern of health risks, primarily an increased risk
Electronic supplementary material The online version of thisarticle (doi:10.1007/s10072-017-2850-8) contains supplementarymaterial, which is available to authorized users.
(a) Included totally or partially in another article – (12)
(b) Data could not be extracted – (1)
22 case-control studies and 5 cohort studies included in the systema�c review
Excluded ar�cles for the following reasons: (n=11)
a) Case Control Studies : Shared identical population= 8
b) Cohort Studies = 5
14 case-control studies included in the meta-analysis
Fig. 1 Selection of relevant studies
Neurol Sci
123
Table 1 Characteristics of included case–control studies
S.
no.
Study ID
(sorted by
year of
publication)
Country
(type of
funding)
Age
range
(years)
Type of
tumour
investigated
Participation rate Overall
results (OR,
95% CI) (if
ever used)
Overall
results (OR,
95% CI) ([10
years use)
Comments
Cases Controls
1. Hardell [3] Sweden (G) 20–80 M, G, AN 90% 91% 0.98
(0.69–0.41)
1.20
(0.56–2.59)
No overall increased risk
of brain tumours
associated with
exposure to cellular
phones
2. Muscat [4] USA (P) 18–80 G 82% 90% 0.85 (0.6–1.2) – Use of handheld cellular
telephones is not
associated with risk of
brain cancer
3. Inskip [5] USA (M) 18? M, G, AN 80% NM Gliomas 1.0
(0.7–1.4)
Meningiomas
0.8
(0.5–1.2)
Acoustic
neuromas
0.8
(0.5–1.4)
– The data is not sufficient
to evaluate the risks
among long-term, heavy
users and for potentially
long induction periods
4. Auvinen [17] Finland 20–69 M, G NM NM Analogue 1.6
(1.1-2.3]
Digital 0.9
(0.5–1.5)
– Cellular phone use was
not associated with brain
tumours, but there was a
weak association
between gliomas and
analogue cellular phones
5. Hardell [16] Sweden 20–80 M, G, AN 88% 91% 1.3 (1.02–1.6) 1.8 (1.1–2.9) Use of analogue cellular
telephones was
associated with
increased risk of brain
tumours
6. Warren [9] USA Not
stated
AN – – Handheld
cellular
telephone
0.6
(0.2–1.9)
Regular
cellular
telephone
0.4
(0.1–2.1)
– Regular cellular telephone
use does not appear to
be associated with a
higher risk of brain
tumour development
7. Hardell [6] Sweden 18–74 M, AN 89% 84% Meningiomas
Analogue 1.7
(0.97–3.0)
Digital 1.3
(0.9–1.9)
Cordless 1.3
(0.9–1.9)
Acoustic
neuromas
Analogue 4.2
(1.8–10)
Digital 2
(1.05–2.8)
Cordless 1.5
(0.8–2.9)
Meningiomas
Analogue 2.1
(1.1–4.3)
Digital 1.5
(0.6–3.9)
Cordless 1.9
(0.97–3.6)
Acoustic
neuromas
Analogue 2.6
(0.9–8)
Digital 0.8
(0.1–6.7)
Cordless 0.3
(0.03–2.2)
The study showed an
increased risk for
acoustic neuromas
associated with
analogue phone use,
regarding meningioma,
a somewhat increase
risk was found
Neurol Sci
123
Table 1 continued
S.
no.
Study ID
(sorted by
year of
publication)
Country
(type of
funding)
Age
range
(years)
Type of
tumour
investigated
Participation rate Overall
results (OR,
95% CI) (if
ever used)
Overall
results (OR,
95% CI) ([10
years use)
Comments
Cases Controls
8. Lonn [10]b Sweden 20–69 G, M Meningiomas Meningiomas
0.7
(0.5–0.9)
Gliomas 0.8
(0.62–1.0)
Meningiomas
0.7
(0.3–1.6)
Gliomas 0.9
(0.5–1.6)
The data do not support
the hypothesis that
mobile phone use is
related to an increased
risk of glioma or
meningioma
74% 85%
Gliomas
71% 85%
9. Schoemaker
[7]a, cDenmark,
Finland,
Norway,
Sweden,
UK
18–69 AN 84% 61% 0.9 (0.7–1.2) 1.8 (1.1–3.1) The study suggests that an
increase in risk of brain
tumour after long-term
use or after a longer lag
period could not be
ruled out
10. Hardell [8] Sweden 20–80 G 88% 84% 2.6 (1.5–4.3) 3.5 (2.0–6.4) The study showed an
increased risk for
malignant brain tumours
associated with the use
of analogue and digital
cellular telephones and
cord-less phones
11. Schuz [15] Denmark 30–69 M, G Meningiomas Meningiomas
0.84
(0.62–1.13)
Gliomas 0.98
(0.75–1.29)
Meningiomas
1.09
(0.35–3.37)
Gliomas 2.20
(0.94–5.11)
The elevated risk of
glioma after 10 or more
years of cellular phone
use needs to be
confirmed by other
studies
88.4% 79.6%
Gliomas
62.7% 79.6%
12. Takebayashi
[11]aJapan 30–69 AN 84.2% 52.4% 0.73
(0.43–1.23)
– The results suggest that
there is no significant
increase in the risk of
acoustic neuroma in
association with mobile
phone use
13. Hours [12]a France 30–59 M, AN, G – – 1.15
(0.65–2.05)
– The results suggest the
possibility of an
increased risk among the
heaviest users
14. Lahkola
[13]b, dDenmark,
Finland,
Sweden,
Norway,
UK
18–69 G 60% 50% 0.78
(0.68–0.91)
0.95
(0.74–1.23)
The overall results do not
indicate an increased
risk of glioma in relation
to mobile phone use
15. Schlehofer
[43]aGermany 30–69 AN 89% 55% 0.67
(0.38–1.19)
– Exposure to ionizing
radiation or to radio
frequency
electromagnetic fields
eg. from mobile phones,
did not increase the risk
of brain tumours
16. Lahkola
[14]bDenmark,
Finland,
Norway,
Sweden,
UK
18–69 M 74% 50% 0.76
(0.65–0.89)
0.85
(0.57–1.26)
The result do not provide
support for an
association between
mobile phone use and
risk of meningioma
Neurol Sci
123
1. While six of nine government funded studies have
a quality score of 7 or 8, all studies funded by
phone industry and mixed sources have a score of
5 or 6.
2. Most of the government funded studies have a high-
quality score of 7, and one has 8.
3. In subgroup meta-analysis on the basis of quality
scores, no significant heterogeneity is seen within a
Table 1 continued
S.
no.
Study ID
(sorted by
year of
publication)
Country
(type of
funding)
Age
range
(years)
Type of
tumour
investigated
Participation rate Overall
results (OR,
95% CI) (if
ever used)
Overall
results (OR,
95% CI) ([10
years use)
Comments
Cases Controls
17. Takebayashi
[26]bJapan 30–69 M, G – 51.2% 1.22
(0.63–2.37)
– No increase in overall risk
of glioma or
meningioma in relation
to regular mobile phone
use
18. Hardell [25] Sweden 20–80 G 75% 67% 1.0 (0.6–1.7) 2.4 (1.4–4.1) An increased risk for
malignant brain tumours
for use of mobile phones
was seen. The risk
increased with latency
and was statistically
significant in the more
than 10 years latency
group
19. Interphone
study
group [27]
13 countries 30–59 M, G Meningiomas Gliomas 0.81
(0.70–0.95)
Meningiomas
0.79
(0.68–0.91)
Gliomas 0.83
(0.61–1.14)
Meningiomas
0.89
(0.76–1.26)
No increase in risk of
gliomas or meningiomas
with use of mobile
phone
78% 64%
Gliomas
53% 64%
20. Interphone
Study
Group (29)
13 countries 30–59 AN 82% 53% 0.85
(0.69–1.04)
0.83
(0.58–1.19)
No increased risk of
acoustic neuroma with
ever regular use of
mobile phone or for
users who began regular
use 10 years or more
21. Aydin [24] Denmark,
Sweden,
Norway,
Switzerland
7–19 G 83.2% 71.1% 1.36
(0.92–2.02)
Brain tumour risk was
related to the time
elapsed since the start of
mobile phone
subscriptions but was
not related to the
amount of use
22. Coureau [42] France 16 years
and
above
M, G 73% 45% Gliomas 1.11
(0.82–1.50)
Meningiomas
0.87
(0.62–1.24)
2.08
(1.07–4.05)
The study provides data
on the relationship
between mobile phone
use and brain tumours.
An increased risk
appears among the
heaviest users, often
with occupational use
and especially of
gliomas
13 countries: Australia, Canada, Denmark, Finland, France, Italy Germany, Japan, New Zealand, Sweden, Norway, UK
G gliomas, M meningiomas, AN acoustic neuromasa Part of data in Interphone study 2011. Not included while updating the meta-analysisb Not included in meta-analysis because already part of data in Interphone study 2010c Schoemaker et al. includes data of studies (meningiomas and acoustic neuromas) by Christensen [48], Christensen [49], Lonn [50], and
Klaeboe [51]d Lakhola et al. includes data of studies (gliomas) by Christensen [49], Hepworth [52] and Klaeboe [51]
Neurol Sci
123
group as compared to heterogeneity across different
quality score groups.
4. Studies with higher quality score show a trend towards
harm, while lower quality score studies show a trend
towards protection.
Mobile phone use of 10 years or longer and risk
of brain tumour
Stratified meta-analysis according to sources of funding
shows a consistent increase in risk of brain tumour with
mobile phone use of more than 10 years. While summary
estimate of government funded studies shows 1.64 times
increase in odds (Supplementary Figure IV), mixed funded
studies show 1.05 times increase in odds of risk of brain
tumours, but the results were not statistically significant
(Supplementary Figure V). The data for more than 10 years
of use were not available for phone industry funded studies.
Metaregression analysis
If ever use of mobile phone
A total of 20 studies were included for random-effects
metaregression. The data on a whole from INTERPHONE
2010 and INTERPHONE 2011 were not included in the
analysis; instead, data from individual studies which were
Table 2 Characteristics of included cohort studies
S.
no.
Study ID
(sorted by year
of publication)
Country Type of
tumour
investigated
Sample
size
Age range
(years; at first
subscription)
Overall
results
Comments
1. Morgan [29] USA All brain
cancers
195,775 – SMR 0.53
(0.21–1.09)
The result do not support an associated
between occupational radiofrequency
exposure and brain cancers
2. Johansen [30]a Denmark M, AN, G 420,095 18–70 SIR 0.95
(0.81–1.12)
The result do not support the hypothesis of an
association between use of telephones and
tumours of the brain
3. Schuz [31]a Denmark M, AN, G 420,095 – SIR brain
tumours
(0.97)
Acoustic
neuromas
(0.73)
[10 years
0.66
(0.44–0.95)
No evidence for an association between
tumour risk and cellular telephone use
among either short-term or long-term users
4. Frei [32] France M, G 358,403 – IRR
[10 years
Glioma 1.04
(0.85–1.26)
in men
1.04
(0.56–1.95)
in women
Meningioma
0.90
(0.57–1.42)
in men
0.93
(0.46–1.87)
in women
No increased risks of tumours of the central
nervous system, providing little evidence for
a causal association
5. Schuz [53]a Denmark AN 29,000,000 – RRE 0.87
(0.52–1.46)
No evidence was found that mobile phone use
is related to the risk of acoustic neuromas
G gliomas, M meningiomas, AN acoustic neuromasa Part of data in Frei 2011
Neurol Sci
123
Study or Subgroup1.10.1 Study Quality 8
Hardell 2006Subtotal (95% CI)
Total eventsHeterogeneity: Not applicableTest for overall effect: Z = 3.27 (P = 0.001)